Plastic floor covering and method for obtaining same

ABSTRACT

A floor covering produced by coating and including a thermoplastic-based structure, in particular plasticized PVC, reinforced with a textile reinforcement, optionally combined with a foam backing. The visible surface consists of a surface coating providing decoration and wear resistance to the product. The back surface, designed to be in contact with the floor, consists of a textile web, the bonding between the textile structure and the supporting back surface being produced by means of an additional plastisol layer, which penetrates over a minor part of the thickness of the textile structure and which, after gelling, bonds the textile to the thermoplastic substrate back surface.

FIELD OF THE INVENTION

The present invention relates to a new type of plastic floor coveringand an improved method implemented to produce said floor covering.

In particular it relates to a floor covering produced according to atechnique called “coating” which presents comfortable walking, acousticand thermal insulation, mechanical resistance and flatness propertiesthat are improved compared to prior products.

BACKGROUND OF THE INVENTION

Flexible plastic floor coverings have been produced for a very longtime.

This type of covering generally comprises a thermoplastic base structurewhich is often reinforced with a textile material embedded in the massof said thermoplastic.

Also, in order to improve the level of comfort and to provide thecovering with insulation and flexibility qualities the reverse surfaceof said covering may be associated with an underlay, for example a foamunderlay.

Furthermore, the upper surface is covered with a finishing layer whichprovides the floor covering with specific properties such as resistanceto UV rays, dirt deposit, scratches, wear, abrasion, etc.

The floor coverings may be produced using different techniques such ascoating, calendering, pressing, etc.

In order to create the floor covering using the coating technique abacking sheet is produced by impregnating a reinforcement textilestructure, which is generally unwoven, the structure very often beingfibreglass based although it can also have a synthetic polymer base,such as polyester, polyamide or polypropylene fibres.

The coating is produced from a plastisol composition, more often thannot PVC based, although it can also be acrylic, polyurethane orpolyolefin based to provide a smooth, flat surface.

Once the backing sheet has been produced the top layer(s) are createdthat are intended to provide the decorative and wear-and-tearcharacteristics. The reverse surface is also produced to ensure thefinish (for compact layers) or comfort and/or insulation by associatinga mechanical or chemical foam-based underlay.

In addition to floor coverings whose upper surface is flat, for manyyears now floor coverings have also been proposed that present embossedeffects, such as those described particularly in GB-A-1 520 964, U.S.Pat. No. 3,399,106 and U.S. Pat. No. 4,244,899, EP-A-0 003 965 and FR 2557 905. When these embossed floor coverings are produced a chemicalfoam, onto which a pattern is printed using inks some of which containexpansion inhibitors, as inserted between the resin-impregnated basestructure and the surface layers.

Once the wear layer has been applied to the pattern thus produced, allthe layers are gelled together which causes different degrees ofexpansion between the inhibited printed zones and the uninhibitedprinted zones and produces an embossed decorative surface, the degree ofexpansion being lower in the inhibited printed zones.

These types of floor coverings, which have proved to be extremelypopular, are widely used nowadays. Nevertheless, they present acousticand thermal insulation characteristics that are sometimes consideredinsufficient.

To overcome the drawback the only proposal envisaged therefore consistedin applying a mechanical or chemical foam to the reverse surface which,if a low-density foam is used, can affect the solidity of the coveringand the plastic feel provided by this type of underlay often discouragespotential buyers.

The level of comfort when walking on the covering is often consideredinsufficient, comfort being the result of several factors such as thefeeling of softness (immediately sinking into the covering) which shouldbe maximum, anti-impact (progressive deceleration) and anti-bounce (nilbouncing speed).

SUMMARY OF THE INVENTION

The purpose of the present invention is to offer an improvement to floorcoverings produced using coating techniques and comprising athermoplastic, particularly plasticized PVC, base structure reinforcedby a fabric backing, possibly associated with a foam underlay, the uppersurface of which consists of a surface coating which provides thecovering with the pattern and resistance to wear.

The material according to the invention is characterised in that thereverse surface intended to be brought into contact with the floorconsists of a textile cloth, preferably unwoven, the link between thetextile structure and the reverse surface of the backing sheet beingcreated by the intermediary of an additional plastisol layer whichpenetrates slightly into the matter of the textile structure and which,after gelling, bonds said textile to the rear of the thermoplasticbacking sheet.

According to a first embodiment the textile structure is fasteneddirectly to the reverse surface of the backing sheet via a plastisollayer which smoothes said surface.

If the reverse surface of the floor covering comprises a layer of foamthe textile structure is bonded via a layer of plastisol.

Although the floor covering according to the invention may have a flatsurface layer said surface layer may also comprise embossed patternsobtained by localised expansion of a layer of foam inserted between thebacking sheet and surface layer(s).

It should be noted that, according to the invention, the textile orunwoven sheet present on the reverse surface of the backing is onlypartially embedded in the plastic layer bonding it to the reverse of thecovering in order to retain the textile feel and characteristics of thecloth.

In general the impregnation by the layer of plastisol is between 0.5 and15% of the total thickness of the textile, preferably between 3 and 10%.

The textile structure intended to create the reverse of the coating ispreferably unwoven, preferably needled and consists advantageously ofpolyester fibres.

The unwoven textile may be calendered and/or thermobonded, the thicknessbeing between 0.5 and 5 millimeters, preferably between 1 and 2millimeters.

It has been observed that if the thickness is less than 0.5 millimetersthe result is a degree of relative impregnation of the bonding plastisolwhich is too high and which affects not only the textile feeling of thereverse surface but also the additional insulation and comfortcharacteristics provided by this type of textile structure.

On the other hand, thickness greater than 5 millimeters does notsignificantly improve the product characteristics but it does presentthe disadvantage of greatly increasing the cost.

The weight per square meter of the unwoven textile applied to thereverse surface may be between 40 and 500 grams but is advantageouslybetween 80 and 300 grams. The elongation capacity is between 30 and120%.

The invention also relates to a method for producing this type ofcovering.

In general, according to the invention, in an initial operating phasestandard techniques are used to produce a base structure by impregnatinga fabric backing, for example a fibreglass surfacing mat, with a PVC oracrylic plastisol or a polyolefin pre-gelled by thermal treatment.

In a second operating phase after printing, a surface coating is thenproduced in a continuous operation.

According to the invention, and preferably in a continuous operationwith those mentioned above, a PVC, acrylic plastisol or polyolefin orother polymer based bonding layer is applied to the reverse surface ofthe complex thus produced, and a textile cloth, which is preferablyunwoven, is applied to this wet layer using sufficient pressure topartially impregnate said cloth with plastisol. The pressure applied isgenerally between 0.1 and 4 bar maximum.

The layers are then gelled together by thermal treatment which enablesthe final complex to be obtained, the gelling or re-heating phasebonding the textile structure on the reverse surface to the plasticsection.

This type of method may be implemented to produce floor coverings thedecorative surface of which is flat but it may also be applied toproduce a floor covering with an embossed decorative surface.

For embossed finishes, once the reinforcement textile has beenimpregnated with a plastisol which is then pre-gelled, for example on adrum heated to 135° C., the surface of this base structure is coatedwith a decorative chemical foam which is also PVC, acrylic or polyolefinbased. The chemical foam is also gelled at 140° C. to achieve a flexiblesheet with a smooth surface onto which a pattern is printed using inkssome of which contain expansion inhibitors.

The wear layer is then applied to the pattern and all the layers aregelled together in an oven by thermal treatment at 195° C.

The decorative chemical foam also expands during this stage.

DETAILED DESCRIPTION

The invention and advantages it offers will be better understood fromthe following concrete examples which are for information only and arenon-limitative.

The examples relate to floor coverings with an embossed decorativesurface produced according to the teachings of U.S. Pat. No. 3,399,106or EP 0 003 965, but these examples are clearly non-limitative.

The formulations, which are expressed in parts by weight, of the variousplastisol compositions included to produce the floor coverings given asexamples are grouped together in the table below.

Also the characteristics of the coverings produced are determined asfollows:

-   -   acoustic insulation: measured according to standard ISO 140-8        and ISO 717-2,    -   temperature: measured by the cold-feet test.

Such a test is performed in a room maintained, to within one degree, at23° C. on a refrigerated bench the temperature of which is maintained at0° C.

The floor covering is applied to the bench and the temperature of theupper surface is measured after 30 minutes.

The higher the temperature, the greater the thermal insulation and thegreater the relief from the feeling of cold feet.

-   -   Comfortable walking: measured according to standards NFP 90-104        and NFP 90-203 and evaluated by the level of softness as        measured when the foot immediately sinks into the covering.

BASE COMPLEX (A) Decora- Reverse Reverse tive surface surface Impreg-chemical Wear Smooth- chemical mechanical nation foam layer ness foamfoam PVC emulsion K 80 (*) 0 0 85 0 0 0 PVC microsuspension K 80 (*) 0 035 50 0 PVC suspension K 100 (*) 0 0 40 0 0 0 PVC emulsion K 75 (*) 75 00 30 0 60 PVC emulsion K 70 (*) 0 95 0 0 0 0 PVC emulsion K 65 (*) 0 0 00 55 PVC suspension K 65 (*) 0 30 0 20 0 40 PVC emulsion K 60 (*) 0 0 00 52.5 0 Dioctylphthalate 55 60 27.2 0 22.2 27.6 Butyl benzyl phthalate0 0 40.3 0 38.7 0 Diisoheptylphthalate 0 0 0 42.6 0 27.8 Dodecylbenzene0 4.2 8.4 7.5 4.2 10.4 Tin stabiliser 0.4 0 4.5 0.8 0 0.5 Epoxidisedsoya bean oil 0 0 5.6 0 0 0 Titanium dioxide 2.5 0.3 0 0 0 0 Zinc oxide0 1.2 0 0 1.3 0 Calcium carbonate 6 μm 20 0 0 15 0 0 Calcium carbonate15 μm 70 30 0 55 60 30 Wetting agent 1.1 0.1 0.3 2.2 0 0 Anti UV 0 0 0.30 0 0 Expanding agent 0 2.4 0 0 6 0 Foaming agent 0 0 0 0 0 2.5Fungicide 0 0 0 0 3.6 0 (*) K = K value

Example 1

This example shows how a standard floor covering is produced by coating.

A sheet of fibreglass, which is 0.4 millimeters thick and which weighs40 grams per square meter, is coated with 390 grams per square meter offilled PVC plastisol the formulation of which, in parts by weight, isshown in the “impregnation” column above.

The sheet thus impregnated is then positioned on a drum heated to 135°C. to be pre-gelled.

The surface of the flexible sheet thus produced is then coated with 320grams per square meter of a PVC plastisol-based decorative chemicalfoam.

The coated structure is then pre-gelled in an oven heated to 140° C.

It is then printed by heliography using inks that may contain inhibitorsto produce an embossed decorative effect.

230 grams per square meter of a wear layer, which is an unfilled PVCplastisol-based layer, is then applied to the printed surface and allthe layers are gelled together in an oven heated to 190° C.

The heat also causes the decorative foam to expand and create theembossed effect.

A base A complex is thus obtained.

In order to produce a standard covering, after the decorative foam hasexpanded a finishing treatment is applied to the reverse surface bycoating the rear with 490 grams per square meter of smoothing PVCplastisol the formulation of which, in parts by weight, is shown in thetable above.

Thus prepared, the floor covering is 2 millimeters thick and weighs 1720grams per square meter.

This type of floor covering is perfectly flat, the reverse surfaceconsisting of the smoothing compact, which is smooth to the touch.

It presents the following main characteristics:

-   -   Acoustic insulation: 7 decibels (dB),    -   Thermal insulation: measured using the cold-feet test: 4° C.,    -   The level of comfort when walking on the covering cannot be        measured due to the stiffness of the covering.

Example 2

This example shows how a floor covering is produced according to theinvention.

Compared to the floor covering produced as standard in example 1,according to the invention, the reverse surface of complex A is coatedwith a smoothing PVC plastisol composition which is also smoothing PVCplastisol-based (see formulation in the table) but which is only coatedat a rate of 160 grams per square meter, and a sheet of unwoven,thermobonded, polyester textile weighing 125 grams per square meter and1.1 millimeter thick is unrolled onto the plastisol while still wet.

Pressure of 1 bar is applied using a compression roller the force ofwhich is adjusted to enable the plastisol to slightly penetrate into thematter of the unwoven sheet.

The layers are then put into an oven heated to 180° C. for the finalgelling and to ensure the bonding of the unwoven sheet.

The floor covering thus prepared is approximately 2 millimeters thickand weighs 1215 grams per square meter. It is perfectly flat. Thereverse surface comprising the unwoven textile is soft, pleasant andwarm to the touch.

The PVC plastisol penetrates approximately 0.08 millimeters into theunwoven textile sheet.

Compared to the standard covering in example 1, which only comprises asmoothing layer on the reverse surface, the covering according to theinvention offers acoustic insulation of 16 decibels (dB) measuredaccording to the same standards, i.e. a significant improvement.

Also, the temperature measured in the cold-feet test is 10° C., i.e. asignificant improvement, and the comfort when walking is evaluated bythe degree of softness, the foot immediately sinking into the coveringto a depth of 1.15 millimeters.

Example 3

This example illustrates a second embodiment of the invention.

In the initial phase a complex A is produced similar to that in example1 and comprising an impregnated fibreglass surfacing mat, a decorativechemical foam and an identical wear layer.

After this complex has been created the reverse surface is coated withchemical foam plastisol the formulation of which is given in the tableabove.

Onto this layer of expanded and calibrated foam a bonding plastisollayer is deposited onto which is unrolled a sheet of unwoven,thermobonded, polyester-based textile weighing 125 grams per squaremeter and the thickness of which is 1.1 millimeters.

Pressure of 1 bar is also applied to enable the plastisol to slightlypenetrate the unwoven sheet.

The layers are then also put into an oven heated to 180° C. for thefinal gelling and to ensure the bonding of the unwoven sheet.

The floor covering thus prepared is approximately 3 millimeters thickand weighs 1,360 grams per square meter.

It is perfectly flat.

The reverse surface comprising the unwoven textile is soft, pleasant andwarm to the touch.

The PVC plastisol penetrates 0.08 millimeters into the unwoven textile.

The acoustic insulation measured is 19 decibels (dB).

The temperature measured in the cold-feet test is 15° C.

The comfort when walking is evaluated by the degree of softness, thefoot immediately sinking into the covering to a depth of 1.32millimeters.

Example 4

As a comparison, this example shows the characteristics presented by astandard floor covering with a PVC mechanical foam underlay.

The only difference between the present example and example 1 is thatinstead of using a smoothing plastisol to create a finishing treatmentof the reverse surface said surface is coated with 980 grams per squaremeter of a PVC mechanical foam plastisol (see formulation in the table).

The layers are then put into an oven heated to 180° C. for the finalgelling.

A floor covering is obtained that is 3 millimeters thick and that weighs2,145 grams per square meter.

This floor covering is perfectly flat but the reverse surface, whichconsists of mechanical foam, is smooth in appearance and is plastic tothe touch.

The acoustic insulation is 15 decibels (dB).

The temperature measured in the cold-feet test is 5° C., i.e.significantly worse than that for the coating made according to theinvention.

The comfort when walking is evaluated by the degree of softness, thefoot immediately sinking into the covering to a depth of 1.01millimeters, i.e. considerably less than that obtained according to theinvention in example 3 despite a significant increase in the thicknessof foam.

The above examples clearly show the advantages provided by the inventionwhich consist not only in a very good level of acoustic insulation, animprovement in the results of the cold-feet test but also excellentcomfort when walking and softness, the reverse surface comprising anunwoven textile also providing the covering with a soft, pleasant andwarm feeling to the touch.

The presence of the textile backing also enables the coating to beimplemented by any system recommended for textile coatings, particularlythe self-adhering-type systems.

1. A floor covering produced using coating techniques, said floorcovering comprising: a fiberglass mat; a thermoplastic base structureimpregnating said fiberglass mat; a surface layer provided on an uppersurface of said impregnated fiberglass mat providing coloring,decoration, and resistance to wear; a plastisol layer adhered to a lowersurface of said impregnated fiberglass mat; and a non-woven polyestertextile web adhered to said plastisol layer, said textile web having athickness between 0.5 and 5.0 millimeters, having an elongation capacitybetween 30 and 120 percent, and having a weight per square meter between80 and 300 grams, said plastisol layer penetrating said textile web adistance between 0.5 and 15 percent of the thickness of said textileweb; wherein said textile web defines a lowermost surface of said floorcovering.
 2. A floor covering as claimed in claim 1, wherein saidthermoplastic base structure comprises plasticized polyvinyl chloride(PVC).
 3. A floor covering as claimed in claim 1, further comprising afoam underlay provided between said lower surface of said impregnatedfiberglass mat and said plastisol layer.
 4. A floor covering as claimedin claim 3, wherein said foam underlay is formed using a plastisolchemical foam.
 5. A floor covering as claimed in claim 3, wherein anacoustic insulation characteristic is about 19 dB, a thermal insulationcharacteristic is 15° C., and a comfort when walking characteristicaccording to NFP 90-104 and NFP 90-203 and evaluated by the level ofsoftness as measured by a depth of a foot sinking into said floorcovering, is about 1.3 mm.
 6. A floor covering as claimed in claim 1,wherein said plastisol layer smooths said impregnated fiberglass mat. 7.A floor covering as claimed in claim 1, wherein said surface layercomprises embossed patterns obtained by a localized expansion of a layerof foam inserted between said upper surface of said impregnatedfiberglass mat and said surface layer.
 8. A floor covering as claimed inclaim 1, wherein an acoustic insulation characteristic is 16 dB, athermal insulation characteristic is 10° C. and a comfort when walkingcharacteristic according to NFP 90-104 and NFP 90-203 and evaluated bythe level of softness as measured by a depth of a foot sinking into saidfloor covering, is about 1.15 mm.